1.\" 2.\" Copyright (c) 1997 Kenneth D. Merry. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. The name of the author may not be used to endorse or promote products 14.\" derived from this software without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $FreeBSD: src/usr.sbin/iostat/iostat.8,v 1.11.2.9 2002/12/29 16:35:41 schweikh Exp $ 29.\" 30.\" Copyright (c) 1985, 1991, 1993 31.\" The Regents of the University of California. All rights reserved. 32.\" 33.\" Redistribution and use in source and binary forms, with or without 34.\" modification, are permitted provided that the following conditions 35.\" are met: 36.\" 1. Redistributions of source code must retain the above copyright 37.\" notice, this list of conditions and the following disclaimer. 38.\" 2. Redistributions in binary form must reproduce the above copyright 39.\" notice, this list of conditions and the following disclaimer in the 40.\" documentation and/or other materials provided with the distribution. 41.\" 3. Neither the name of the University nor the names of its contributors 42.\" may be used to endorse or promote products derived from this software 43.\" without specific prior written permission. 44.\" 45.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 46.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 47.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 48.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 49.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 50.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 51.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 52.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 53.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 54.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 55.\" SUCH DAMAGE. 56.\" 57.\" @(#)iostat.8 8.1 (Berkeley) 6/6/93 58.\" 59.Dd December 22, 1997 60.Dt IOSTAT 8 61.Os 62.Sh NAME 63.Nm iostat 64.Nd report 65.Tn I/O 66statistics 67.Sh SYNOPSIS 68.Nm 69.Op Fl CdhKIoT 70.Op Fl c Ar count 71.Op Fl n Ar devs 72.Oo 73.Fl t 74.Sm off 75.Ar type , if , pass 76.Sm on 77.Oc 78.Op Fl w Ar wait 79.Op Ar drives 80.Sh DESCRIPTION 81.Nm Iostat 82displays kernel 83.Tn I/O 84statistics on terminal, device and cpu 85operations. 86.Pp 87The options are as follows: 88.Bl -tag -width flag 89.It Fl c 90Repeat the display 91.Ar count 92times. 93If no 94.Ar wait 95interval is specified, the default is 1 second. 96.It Fl C 97Display CPU statistics. 98This is on by default, unless 99.Fl d 100is specified. 101.It Fl d 102Display only device statistics. 103If this flag is turned on, only device statistics will be displayed, unless 104.Fl C 105or 106.Fl T 107is also specified to enable the display of CPU or TTY statistics. 108.It Fl D 109Display more details. 110If this flag is turned on, details on read and write statistics will be 111displayed as MBw/s (Megabyte written per second), MBr/s (Megabyte read per second), 112rtps (read transactions per second) and wtps (write transactions per second). 113.It Fl h 114Put 115.Nm 116in 117.Sq top 118mode. 119In this mode, 120.Nm 121will show devices in order from highest to lowest bytes 122per measurement cycle. 123.It Fl I 124Display total statistics for a given time period, rather than average 125statistics for each second during that time period. 126.It Fl K 127In the blocks transferred display (-o), display block count in kilobytes rather 128then the device native block size. 129.It Fl n 130Display up to 131.Ar devs 132number of devices. 133.Nm 134will display fewer devices if there aren't 135.Ar devs 136devices present. 137.It Fl o 138Display old-style 139.Nm 140device statistics. 141Sectors per second, transfers per second, and milliseconds per seek are 142displayed. 143If 144.Fl I 145is specified, total blocks/sectors, total transfers, and 146milliseconds per seek are displayed. 147.It Fl t 148Specify which types of devices to display. 149There are three different categories of devices: 150.Pp 151.Bl -tag -width indent -compact 152.It device type: 153.Bl -tag -width 9n -compact 154.It da 155Direct Access devices 156.It sa 157Sequential Access devices 158.It printer 159Printers 160.It proc 161Processor devices 162.It worm 163Write Once Read Multiple devices 164.It cd 165CD devices 166.It scanner 167Scanner devices 168.It optical 169Optical Memory devices 170.It changer 171Medium Changer devices 172.It comm 173Communication devices 174.It array 175Storage Array devices 176.It enclosure 177Enclosure Services devices 178.It floppy 179Floppy devices 180.El 181.Pp 182.It interface: 183.Bl -tag -width 9n -compact 184.It IDE 185Integrated Drive Electronics devices 186.It SCSI 187Small Computer System Interface devices 188.It other 189Any other device interface 190.El 191.Pp 192.It passthrough: 193.Bl -tag -width 9n -compact 194.It pass 195Passthrough devices 196.El 197.El 198.Pp 199The user must specify at least one device type, and may specify at most 200one device type from each category. 201Multiple device types in a single device type statement must be separated by 202commas. 203.Pp 204Any number of 205.Fl t 206arguments may be specified on the command line. 207All 208.Fl t 209arguments are ORed together to form a matching expression against which 210all devices in the system are compared. 211Any device that fully matches any 212.Fl t 213argument will be included in the 214.Nm 215output, up to the number of devices that can be displayed in 216available columns (80 minimum), or the maximum number of devices specified 217by the user. 218.It Fl T 219Display TTY statistics. 220This is on by default, unless 221.Fl d 222is specified. 223.It Fl w 224Pause 225.Ar wait 226seconds between each display. 227If no repeat 228.Ar count 229is specified, the default is infinity. 230.El 231.Pp 232.Nm Iostat 233displays its information in the following format: 234.Bl -tag -width flag 235.It tty 236.Bl -tag -width indent -compact 237.It tin 238characters read from terminals 239.It tout 240characters written to terminals 241.El 242.It devices 243Device operations. 244The header of the field is the device name and unit number. 245.Nm 246will display as many devices as will fit in available columns (80 minimum), 247or the maximum number of devices in the system, whichever is smaller. 248If 249.Fl n 250is specified on the command line, 251.Nm 252will display the smaller of the 253requested number of devices, and the maximum number of devices in the system. 254To force 255.Nm 256to display specific drives, their names may be supplied on the command 257line. 258.Nm 259will not display more devices than will fit in available columns (80 columns 260minimum), unless the 261.Fl n 262argument is given on the command line to specify a maximum number of 263devices to display. 264Fewer devices may be displayed. 265.Pp 266The standard 267.Nm 268device display shows the following statistics: 269.Pp 270.Bl -tag -width indent -compact 271.It KB/t 272kilobytes per transfer 273.It tps 274transfers per second 275.It MB/s 276megabytes per second 277.El 278.Pp 279The standard 280.Nm 281device display, with the 282.Fl I 283flag specified, shows the following statistics: 284.Pp 285.Bl -tag -width indent -compact 286.It KB/t 287kilobytes per transfer 288.It xfrs 289total number of transfers 290.It MB 291total number of megabytes transferred 292.El 293.Pp 294The old-style 295.Nm 296display (using 297.Fl o ) 298shows the following statistics: 299.Pp 300.Bl -tag -width indent -compact 301.It sps 302sectors transferred per second 303.It tps 304transfers per second 305.It msps 306average milliseconds per transaction 307.El 308.Pp 309The old-style 310.Nm 311display, with the 312.Fl I 313flag specified, shows the following statistics: 314.Pp 315.Bl -tag -width indent -compact 316.It blk 317total blocks/sectors transferred 318.It xfr 319total transfers 320.It msps 321average milliseconds per transaction 322.El 323.It cpu 324.Bl -tag -width indent -compact 325.It \&us 326% of cpu time in user mode 327.It \&ni 328% of cpu time in user mode running niced processes 329.It \&sy 330% of cpu time in system mode 331.It \&in 332% of cpu time in interrupt mode 333.It \&id 334% of cpu time in idle mode 335.El 336.El 337.Sh EXAMPLES 338.Dl iostat -w 1 da0 da1 cd0 339.Pp 340Display statistics for the first two Direct Access devices and the first 341CDROM device every second ad infinitum. 342.Pp 343.Dl iostat -c 2 344.Pp 345Display the statistics for the first four devices in the system twice, with 346a one second display interval. 347.Pp 348.Dl iostat -t da -t cd -w 1 349.Pp 350Display statistics for all CDROM and Direct Access devices every second 351ad infinitum. 352.Pp 353.Dl iostat -t da,scsi,pass -t cd,scsi,pass 354.Pp 355Display statistics once for all SCSI passthrough devices that provide access 356to either Direct Access or CDROM devices. 357.Pp 358.Dl iostat -h -n 8 -w 1 359.Pp 360Display up to 8 devices with the most I/O every second ad infinitum. 361.Pp 362.Dl iostat -dh -t da -w 1 363.Pp 364Omit the TTY and CPU displays, show devices in order of performance and 365show only Direct Access devices every second ad infinitum. 366.Pp 367.Dl iostat -Iw 3 368.Pp 369Display total statistics every three seconds ad infinitum. 370.Pp 371.Dl iostat -odICTw 2 -c 9 372.Pp 373Display total statistics using the old-style output format 9 times, with 374a two second interval between each measurement/display. 375The 376.Fl d 377flag generally disables the TTY and CPU displays, but since the 378.Fl T 379and 380.Fl C 381flags are given, the TTY and CPU displays will be displayed. 382.Sh SEE ALSO 383.Xr fstat 1 , 384.Xr netstat 1 , 385.Xr nfsstat 1 , 386.Xr ps 1 , 387.Xr systat 1 , 388.Xr pstat 8 , 389.Xr vmstat 8 390.Pp 391The sections starting with ``Interpreting system activity'' in 392.%T "Installing and Operating 4.3BSD" . 393.Sh HISTORY 394This version of 395.Nm 396first appeared in 397.Fx 3.0 . 398.Sh AUTHORS 399.An Kenneth Merry Aq Mt ken@FreeBSD.org 400